A set of essentially identical panels, such as building panels, provided with a mechanical locking system including a displaceable tongue arranged in a displacement groove having a first opening at a first edge of a first panel. The tongue is configured to be displaced in the displacement groove along a displacement axis to attain a locking state wherein a first portion of the tongue cooperates with a first tongue groove having a second opening at a second edge of an adjacent second panel, for vertical locking of the first and the second edge. A second portion of the tongue is configured to cooperate with the second edge of the adjacent second panel via an elongated element for vertical unlocking of the first and the second edge.

A panel is disclosed for use in construction. The panel comprises opposing surfaces that extend between first and second opposite ends. The panel also comprises a plurality of parallel (e.g. sawtooth) ridges. The ridges are provided on at least one of the opposing surfaces. The ridges extend along and adjacent to a first of the opposite ends of the panel for at least a part length thereof. The ridges are arranged to engage with and move past corresponding ridges of an adjacent panel when the panels move relative to each other in opposite directions. The ridges are further arranged so as to interfere with the ridges of the adjacent panel to resist relative movement in a reverse of the opposite direction.

A panel is disclosed for use in construction. The panel comprises opposing surfaces that extend between first and second opposite ends. The panel also comprises a plurality of parallel (e.g. sawtooth) ridges. The ridges are provided on at least one of the opposing surfaces. The ridges extend along and adjacent to a first of the opposite ends of the panel for at least a part length thereof. The ridges are arranged to engage with and move past corresponding ridges of an adjacent panel when the panels move relative to each other in opposite directions. The ridges are further arranged so as to interfere with the ridges of the adjacent panel to resist relative movement in a reverse of the opposite direction.

A structural reinforced composite construction mat includes a plurality of composite plastic beams that are ganged together to define the mat, with a plurality of flitch plates disposed between at least some of the plastic beams to provide additional strength and rigidity to the mat. The plastic beams may be made of a composite material have a generally rectangular cross-section. The flitch plates have a width (vertical height) when disposed between adjacent beams that is less than the width (vertical height) of the beams, such that the flitch plates may be recessed below and above the top and bottom surfaces of the mat, respectively. A plurality of rods extend in the lateral direction through the beams and plates to compress the beams and plates against each. The flitch plates may be metal or fiber-reinforced resin and may further include slotted holes to allow the beams to retract lengthwise in response to environmental changes.

A structural reinforced composite construction mat includes a plurality of composite plastic beams that are ganged together to define the mat, with a plurality of flitch plates disposed between at least some of the plastic beams to provide additional strength and rigidity to the mat. The plastic beams may be made of a composite material have a generally rectangular cross-section. The flitch plates have a width (vertical height) when disposed between adjacent beams that is less than the width (vertical height) of the beams, such that the flitch plates may be recessed below and above the top and bottom surfaces of the mat, respectively. A plurality of rods extend in the lateral direction through the beams and plates to compress the beams and plates against each. The flitch plates may be metal or fiber-reinforced resin and may further include slotted holes to allow the beams to retract lengthwise in response to environmental changes.

Modular building methods and systems using lightweight modular panels, and specially configured transition panels for transitioning from wall to floor, or from wall to roof. Identically configured standard panels are used for constructing the walls, floor, and roof, with transitions from one structure to the next (e.g., wall to floor, or wall to roof). Each of the variously configured panel types includes channels (e.g., 2 pair of channels) formed through the length of the foam body, where the channels are configured to receive splines (e.g., flanges of an I-beam) therein. In the standard panel, the channels may include pairs of top and bottom channels, with the channels offset towards the respective panel major faces. In the transition panels, the channels may be similarly configured, but positioned differently to make the appropriate transition. The splines are connected to a frame, which acts as a template and transfers loads to a foundation.

A structural reinforced composite construction mat includes a plurality of composite plastic beams that are ganged together to define the mat, with a plurality of flitch plates disposed between at least some of the plastic beams to provide additional strength and rigidity to the mat. The plastic beams may be made of a composite material have a generally rectangular cross-section. The flitch plates have a width (vertical height) when disposed between adjacent beams that is less than the width (vertical height) of the beams, such that the flitch plates may be recessed below and above the top and bottom surfaces of the mat, respectively. A plurality of rods extend in the lateral direction through the beams and plates to compress the beams and plates against each. The flitch plates may be metal or fiber-reinforced resin and may further include slotted holes to allow the beams to retract lengthwise in response to environmental changes.

A structural reinforced composite construction mat includes a plurality of composite plastic beams that are ganged together to define the mat, with a plurality of flitch plates disposed between at least some of the plastic beams to provide additional strength and rigidity to the mat. The plastic beams may be made of a composite material have a generally rectangular cross-section. The flitch plates have a width (vertical height) when disposed between adjacent beams that is less than the width (vertical height) of the beams, such that the flitch plates may be recessed below and above the top and bottom surfaces of the mat, respectively. A plurality of rods extend in the lateral direction through the beams and plates to compress the beams and plates against each. The flitch plates may be metal or fiber-reinforced resin and may further include slotted holes to allow the beams to retract lengthwise in response to environmental changes.

An apparatus for resisting a gravity load is disclosed. The apparatus has a first end member, a second end member, and a plurality of elongated structural members, each of the plurality of elongated structural members including a first end portion attached to the first end member and a second end portion attached to the second end member. The plurality of elongated structural members is oriented to resist compressive stresses or tensile stresses induced by the gravity load. The plurality of elongated structural members is formed from plants with a harvest cycle of four years or fewer.

An apparatus for resisting a gravity load is disclosed. The apparatus has a first end member, a second end member, and a plurality of elongated structural members, each of the plurality of elongated structural members including a first end portion attached to the first end member and a second end portion attached to the second end member. The plurality of elongated structural members is oriented to resist compressive stresses or tensile stresses induced by the gravity load. The plurality of elongated structural members is formed from plants with a harvest cycle of four years or fewer.